US20220295429A1 - Multi-member bluetooth device capable of synchronizing audio playback between different bluetooth circuits - Google Patents
Multi-member bluetooth device capable of synchronizing audio playback between different bluetooth circuits Download PDFInfo
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- 238000004891 communication Methods 0.000 claims description 66
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- 230000005540 biological transmission Effects 0.000 claims description 9
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/02—Speed or phase control by the received code signals, the signals containing no special synchronisation information
- H04L7/027—Speed or phase control by the received code signals, the signals containing no special synchronisation information extracting the synchronising or clock signal from the received signal spectrum, e.g. by using a resonant or bandpass circuit
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/001—Synchronization between nodes
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
- H04B5/70—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes
- H04B5/72—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes for local intradevice communication
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/0008—Synchronisation information channels, e.g. clock distribution lines
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/80—Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks
- H04W84/20—Master-slave selection or change arrangements
Definitions
- the disclosure generally relates to a Bluetooth technology and, more particularly, to a multi-member Bluetooth device capable of synchronizing audio playback among different Bluetooth circuits.
- a multi-member Bluetooth device is a Bluetooth device formed by multiple Bluetooth circuits cooperating with each other, such as a pair of Bluetooth earphones, a set of Bluetooth speakers, or the like.
- the remote Bluetooth device treats the multi-member Bluetooth device as a single Bluetooth device.
- the source Bluetooth device acts as a master in a first piconet.
- the multi-member Bluetooth device comprises: a main Bluetooth circuit, comprising: a first Bluetooth communication circuit; a first clock adjusting circuit; a first control circuit, coupled with the first Bluetooth communication circuit and the first clock adjusting circuit, arranged to operably control the main Bluetooth circuit to act as a slave in the first piconet, and to act as a master in a second piconet; a first sampling-clock adjusting circuit, coupled with the first control circuit; and a first asynchronous sample rate conversion circuit, coupled with the first sampling-clock adjusting circuit, arranged to operably sample a first audio data based on a first audio sampling clock, and to operably transmit sampled data to a first playback circuit for playback; and an auxiliary Bluetooth circuit, comprising: a second Bluetooth communication circuit; a second clock adjusting circuit; a second control circuit, coupled with the second.
- Bluetooth communication circuit and the second clock adjusting circuit arranged to operably control the auxiliary Bluetooth circuit to act as a slave in the second piconet; a second sampling-clock adjusting circuit, coupled with the second control circuit; and a second asynchronous sample rate conversion circuit, coupled with the second sampling-clock adjusting circuit, arranged to operably sample a second audio data based on a second audio sampling clock, and to operably transmit sampled data to a second playback circuit for playback;
- the first control circuit is further arranged to operably conduct following operations: controlling the first clock adjusting circuit to generate a first slave clock and a second main clock according to a timing data of a first main clock generated by the source Bluetooth device, so that both the first slave clock and the second main clock are synchronized with the first main clock; and controlling the first Bluetooth communication circuit to transmit or receive packets in the first piconet according to the first slave clock, and controlling the first Bluetooth communication circuit to transmit or receive packets in the second piconet according to the second main clock; wherein the second control circuit is further arranged
- FIG. 1 shows a simplified functional block diagram of a multi-member Bluetooth device according to one embodiment of the present disclosure.
- FIG. 2 shows a simplified flowchart of a method for synchronizing audio playback operations of different Bluetooth circuits according to one embodiment of the present disclosure.
- FIG. 3 shows a simplified schematic diagram of a scatternet formed by the multi-member Bluetooth device of FIG, 1 according to one embodiment of the present disclosure.
- FIG. 4 shows a simplified flowchart of a method for synchronizing audio playback operations of different Bluetooth circuits according to another embodiment of the present disclosure.
- FIG. 1 shows a simplified functional block diagram of a multi-member Bluetooth device 100 according to one embodiment of the present disclosure.
- the multi-member Bluetooth device 100 is arranged to operably conduct data transmission with a source Bluetooth device 102 , and comprises multiple member circuits.
- a source Bluetooth device 102 comprises multiple member circuits.
- only two member circuits are illustrated in the embodiment of FIG. 1 , which respectively are a main Bluetooth circuit 110 and an auxiliary Bluetooth circuit 120 .
- the main Bluetooth circuit 110 comprises a first Bluetooth communication circuit 111 , a first packet parsing circuit 112 , a first clock adjusting circuit 113 , a first control circuit 114 , a first buffer circuit 115 , a first sampling-clock adjusting circuit 116 , a first asynchronous sample rate conversion circuit 117 , and a first playback circuit 118 .
- the auxiliary Bluetooth circuit 120 comprises a second Bluetooth communication circuit 121 , a second packet parsing circuit 122 , a second clock adjusting circuit 123 , a second. control circuit 124 , a second buffer circuit 125 , a second sampling-clock adjusting circuit 126 , a second asynchronous sample rate conversion circuit 127 , and a second playback circuit 128 .
- the first Bluetooth communication circuit 111 is arranged to operably conduct data communication with other Bluetooth devices.
- the first packet parsing circuit 112 is arranged to operably parse packets received by the first Bluetooth communication circuit 111 .
- the first clock adjusting circuit 113 is arranged to operably adjust partial working clock signals adopted by the main Bluetooth circuit 110 so as to synchronize a piconet clock adopted by the main Bluetooth circuit 110 and other Bluetooth devices,
- the first control circuit 114 is coupled with the first Bluetooth communication circuit 111 , the first packet parsing circuit 112 , and the first clock adjusting circuit 113 , and is arranged to operably control the operations of the aforementioned circuits.
- the first control circuit 114 may directly conduct data communication with the source Bluetooth device 102 through the first Bluetooth communication circuit 111 by using a Bluetooth wireless transmission approach, and may conduct data communication with other member circuits through the first Bluetooth communication circuit 111 .
- the first control circuit 114 may further utilize the first packet parsing circuit 112 to parse the packets received by the first Bluetooth communication circuit 111 so as to acquire related data or instructions.
- the first buffer circuit 115 is arranged to operably store audio data for playback (hereinafter referred to as first audio data).
- first audio data may be audio data pre-stored in the first buffer circuit 115 by the manufacturers or users, audio data transmitted from source Bluetooth device 102 , audio data transmitted from other Bluetooth circuits (e.g., the auxiliary Bluetooth circuit 120 ), or audio data transmitted from other circuits.
- the first sampling-clock adjusting circuit 116 is coupled with the first control circuit 114 , and is arranged to operably generate a first audio sampling clock under control of the first control circuit 114 .
- the first asynchronous sample rate conversion circuit 117 is coupled with the first sampling-clock adjusting circuit 116 and the first playback circuit 118 .
- the first asynchronous sample rate conversion circuit 117 is arranged to operably sample the first audio data in the first buffer circuit 115 based on the first audio sampling clock, and to operably transmit sampled data to the first playback circuit 118 for playback.
- the second Bluetooth communication circuit 121 is arranged to operably conduct data communication with other Bluetooth devices.
- the second packet parsing circuit 122 is arranged to operably parse the packets received by the second Bluetooth communication circuit 121 .
- the second clock adjusting circuit 123 is arranged to operably adjust partial working clock signals adopted by the auxiliary Bluetooth circuit 120 so as to synchronize a piconet clock adopted by the auxiliary Bluetooth circuit 120 and other Bluetooth devices.
- the second control circuit 124 is coupled with the second Bluetooth communication circuit 121 , the second packet parsing circuit 122 , and the second clock adjusting circuit 123 , and is arranged to operably control the operations of the aforementioned circuits.
- the second control circuit 124 may conduct data communication with other Bluetooth devices through the second Bluetooth communication circuit 121 by using the Bluetooth wireless transmission approach, and may conduct data communication with other member circuits through the second Bluetooth communication circuit 121 .
- the second control circuit 124 may further utilize the second packet parsing circuit 122 to parse the packets received by the second Bluetooth communication circuit 121 so as to acquire related data or instructions.
- the second buffer circuit 125 is arranged to operably store audio data for playback (hereinafter referred to as second audio data), in practice, the aforementioned second audio data may be audio data pre-stored in the second buffer circuit 125 by the manufacturers or users, audio data transmitted from source Bluetooth device 102 , audio data transmitted from other Bluetooth circuits (e.g., the main Bluetooth circuit 110 ), or audio data transmitted from other circuits.
- second audio data may be audio data pre-stored in the second buffer circuit 125 by the manufacturers or users, audio data transmitted from source Bluetooth device 102 , audio data transmitted from other Bluetooth circuits (e.g., the main Bluetooth circuit 110 ), or audio data transmitted from other circuits.
- the second sampling-clock adjusting circuit 126 is coupled with the second control circuit 124 , and is arranged to operably generate a second audio sampling clock under control of the second control circuit 124 .
- the second asynchronous sample rate conversion circuit 127 is coupled with the second sampling-clock adjusting circuit 126 and the second playback circuit 128 .
- the second asynchronous sample rate conversion circuit 127 is arranged to operably sample the second audio data in the second buffer circuit 125 based on the second audio sampling clock, and to operably transmit sampled data to the second playback circuit 128 for playback.
- each of the aforementioned first Bluetooth communication circuit 111 and second. Bluetooth communication circuit 121 may be realized with appropriate wireless communication circuits supporting various versions of Bluetooth communication protocols.
- Each of the aforementioned first packet parsing circuit 112 and the second packet parsing circuit 122 may be realized with various packet demodulating circuits, digital processing circuits, micro-processors, or ASICs (Application Specific integrated Circuits).
- Each of the aforementioned first clock adjusting circuit 113 , second clock adjusting circuit 123 , first sampling-clock adjusting circuit 116 , and the second sampling-clock adjusting circuit 126 may be realized with various appropriate circuits capable of comparing and adjusting clock frequency and/or clock phase, such as various PLLs (phase-locked loops) or DLLs (delay-locked loops) or the like.
- Each of the aforementioned first control circuit 114 and the second control circuit 124 may be realized with various micro-processors or digital signal processing circuits having appropriate computing capability.
- Each of the aforementioned first buffer circuit 115 and second buffer circuit 125 may be realized with various volatile memory circuits or non-volatile memory circuits.
- Each of the aforementioned first asynchronous sample rate conversion circuit 117 and second asynchronous sample rate conversion circuit 127 may be realized with various appropriate digital circuits, analog circuits, or digital/analog hybrid circuits.
- Each of the aforementioned first playback circuit 118 and second playback circuit 128 may be realized with various appropriate digital audio playback circuits, analog audio playback circuits, or digital/analog hybrid audio playback circuits.
- the first clock adjusting circuit 113 or the second clock adjusting circuit 123 may be respectively integrated into the first control circuit 114 or the second control circuit 124 .
- the first sampling-clock adjusting circuit 116 or the second sampling-clock adjusting circuit 126 may be respectively integrated into the first control circuit 114 or the second control circuit 124 .
- the aforementioned first packet parsing circuit 112 and the second packet parsing circuit 122 may be respectively integrated into the aforementioned first Bluetooth communication circuit 111 and second Bluetooth communication circuit 121 .
- first Bluetooth communication circuit 111 and first packet parsing circuit 112 may be realized with separate circuits, or may be realized with the same circuit.
- second Bluetooth communication circuit 121 and second packet parsing circuit 122 may be realized with separate circuits, or may be realized with the same circuit.
- different functional blocks of the aforementioned main Bluetooth circuit 110 may be integrated into a single circuit chip.
- all functional blocks of the main Bluetooth circuit 110 or functional blocks except the first playback circuit 118 of the main Bluetooth circuit 110 may be integrated into a single Bluetooth controller IC.
- all functional blocks of the auxiliary Bluetooth circuit 120 or functional blocks except the second playback circuit 128 of the auxiliary Bluetooth circuit 120 may be integrated into another single Bluetooth controller IC.
- the multi-member Bluetooth device 100 may be realized with a Bluetooth device formed by multiple Bluetooth circuits cooperating with each other, such as a pair of Bluetooth earphones, a set of Bluetooth speakers, or the like.
- the source Bluetooth device 102 may be realized with various electronic apparatuses with Bluetooth communication function such as computers, mobile phones, tablet computers, smart speakers, or game consoles, or the like.
- different member circuits of the multi-member Bluetooth device 100 may conduct data communication with one another through respective Bluetooth communication circuits, so as to form various types of Bluetooth network.
- the source Bluetooth device 102 treats the multi-member Bluetooth device 100 as a single Bluetooth device.
- the main Bluetooth circuit 110 may adopt various existing mechanisms to receive the packets issued from the source Bluetooth device 102 , and during the operation of the main Bluetooth circuit 110 , the auxiliary Bluetooth circuit 120 may acquire the packets issued from the source Bluetooth device 102 by adopting appropriate mechanisms.
- the auxiliary Bluetooth circuit 120 may operate at a sniffing mode to actively sniff the packets issued from the source Bluetooth device 102 .
- the auxiliary Bluetooth circuit 120 may operate at a relay mode to passively receive the packets forwarded from the main Bluetooth circuit 110 after the packets issued from the source Bluetooth device 102 are received by the main Bluetooth circuit 110 , and the auxiliary Bluetooth circuit 120 does not actively sniff the packets issued from the source Bluetooth device 102 .
- main Bluetooth circuit and “auxiliary Bluetooth circuit” used throughout the description and claims are merely for the purpose of distinguishing different approaches of receiving packets issued from the source Bluetooth device 102 adopted by different member circuits, rather than indicating that the main Bluetooth circuit 110 is required to have a specific level of control authority over other operational aspects of the auxiliary Bluetooth circuit 120 .
- the main Bluetooth circuit 110 and the auxiliary Bluetooth circuit 120 may exchange their roles with each other intermittently, periodically, or in situations where specific conditions are matched.
- FIG. 2 shows a simplified flowchart of a method for synchronizing audio playback operations of different Bluetooth circuits according to one embodiment of the present disclosure.
- FIG. 3 shows a simplified schematic diagram of a scatternet formed by the multi-member Bluetooth device 100 according to one embodiment of the present disclosure.
- operations within a column under the name of a specific device are operations to be performed by the specific device.
- operations within a column under the label “source Bluetooth device” are operations to be performed by the source Bluetooth device 102 ; operations within a column under the label “main Bluetooth circuit” are operations to be performed by the main Bluetooth circuit 110 ; operations within a column under the label “auxiliary Bluetooth circuit” are operations to be performed by the auxiliary Bluetooth circuit 120 .
- source Bluetooth device is operations to be performed by the source Bluetooth device 102
- operations within a column under the label “main Bluetooth circuit” are operations to be performed by the main Bluetooth circuit 110 ;
- operations within a column under the label “auxiliary Bluetooth circuit” are operations to be performed by the auxiliary Bluetooth circuit 120 .
- the same analogous arrangement also applies to the subsequent flowcharts.
- the main Bluetooth circuit 110 of the multi-member Bluetooth device 100 performs the operation 202 with the source Bluetooth device 102 so as to utilize various methods complying with Bluetooth communication protocols to form a first piconet 310 as shown in FIG. 3 .
- the source Bluetooth device 102 acts as a master in the first piconet 310
- the main Bluetooth circuit 110 of the multi-member Bluetooth device 100 acts as a slave in the first piconet 310 .
- the source Bluetooth device 102 generates a first main clock CLK_P 1 M, and schedules the transmission or reception of Bluetooth packets in the first piconet 310 based on the first main clock CLK_P 1 M, Therefore, the first main clock CLK_P 1 M is not only a native system clock of the source Bluetooth device 102 but also a master clock of the first piconet 310 simultaneously.
- the source Bluetooth device 102 generates and transmits a first piconet timing packet comprising a timing data of the first main clock CLK_P 1 M to the first piconet 310 .
- the source Bluetooth device 102 may utilize various appropriate data to be the timing data of the first main clock CLK_P 1 M.
- the source Bluetooth device 102 may utilize a count value of a specific edge of the first main clock CLK_P 1 M (e.g., the rising edge) to be the timing data of the first main clock CLK_P 1 M, and writes the count value corresponding to the first main clock CLK_P 1 M into a FHS packet (frequency hop synchronization packet) so as to form the first piconet timing packet.
- a FHS packet frequency hop synchronization packet
- the main Bluetooth circuit 110 is arranged to operably generate a first slave clock CLK_P 1 S 1 according to the timing data of the first main clock CLK_P 1 M, so that the first slave clock CLK_P 1 S 1 is synchronized with the first main clock CLK_P 1 M and utilized to be a slave clock in the first piconet 310 .
- the first Bluetooth communication circuit 111 may receive the first piconet timing packet generated by the source Bluetooth device 102 through the first piconet 310 , the first control circuit 114 may control the first packet parsing circuit 112 to acquire the timing data (such as a relevant count value) of the aforementioned first main clock CLK_P 1 M from the first piconet timing packet,
- the first control circuit 114 is arranged to operably control the first clock adjusting circuit 113 to generate a first slave clock CLK_P 1 S 1 according to the timing data of the first main clock CLK_P 1 M, so that the first slave clock CLK_P 1 S 1 is synchronized with the first main clock CLK_P 1 M.
- the first control circuit 114 may control the first clock adjusting circuit 113 to adjust a frequency and/or a phase offset of a first reference clock CLK_R 1 according to the timing data of the first main clock CLK_P 1 M, so as to generate the first slave clock CLK_P 1 S 1 having a frequency substantially identical to the frequency of the first main clock CLK_P 1 M and a phase substantially aligned with the phase of the first main clock CLK_P 1 M.
- the aforementioned first reference clock CLK_R 1 may be generated by various appropriate clock generating circuits located inside or outside the main Bluetooth circuit 110 .
- the first control circuit 114 is arranged to operably control the first Bluetooth communication circuit 111 to schedule the transmission or reception of the Bluetooth packets in the first piconet 310 based on the first slave clock CLK_P 1 S 1 .
- the main Bluetooth circuit 110 and the auxiliary Bluetooth circuit 120 of the multi-member Bluetooth device 100 may utilize various methods complying with Bluetooth communication protocols to form a second piconet 320 as shown in FIG. 3 .
- the main Bluetooth circuit 110 acts as the master in the second piconet 320
- the auxiliary Bluetooth circuit 120 acts as the slave in the second piconet 320 .
- the main Bluetooth circuit 110 is not only a member of the aforementioned first piconet 310 but also a member of the second piconet 320 simultaneously.
- the first control circuit 114 is arranged to operably control the first clock adjusting circuit 113 to generate a second main clock CLK_P 2 M according to the timing data of the first main clock CLK_P 1 M or the timing data of the first slave clock CLK_P 1 S 1 , so that the second main clock CLK_P 2 M is synchronized with the first main clock CLK_P 1 M.
- the first control circuit 114 may control the first clock adjusting circuit 113 to adjust the frequency and/or the phase offset of the aforementioned first reference clock CLK_R 1 according to the timing data of the first main clock CLK_P 1 M or the timing data of the first slave clock CLK_P 1 S 1 so as to generate the second main clock CLK_P 2 M having a frequency substantially identical to the frequency of the first main clock CLK_P 1 M and a phase substantially aligned with the phase of the first main clock CLK_P 1 M.
- the first control circuit 114 is arranged to operably control the first Bluetooth communication circuit 111 to schedule the transmission or reception of the Bluetooth packets in the second piconet 320 based on the second main clock CLK_P 2 M. Therefore, the second main clock CLK_P 2 M is not only the native system clock of the main Bluetooth circuit 110 but also the master clock in the second piconet 320 simultaneously.
- both the first slave clock CLK_P 1 S 1 and the second main clock CLK_P 2 M generated by the first clock adjusting circuit 113 are synchronized with the first main clock CLK_P 1 M generated by the source Bluetooth device 102 . That is, both the frequency of the first slave clock CLK_P 1 S 1 and the frequency of the second main clock CLK_P 2 M are substantially identical to the frequency of the first main clock CLK_P 1 M, and both the phase of the first slave clock CLK_P 1 S 1 and the phase of the second main clock CLK_P 2 M are substantially aligned with the phase of the first main clock CLK_P 1 M.
- the first control circuit 114 may respectively assign different count values to the aforementioned first slave clock CLK_P 1 S 1 and second main clock CLK_P 2 M.
- the aforementioned method for synchronizing the first slave clock CLK_P 1 S 1 and the second main clock CLK_P 2 M of the main Bluetooth circuit 110 can effectively increase the Bluetooth bandwidth utilization efficiency of the main Bluetooth circuit 110 .
- the first control circuit 114 is further arranged to operably generate a second piconet timing packet comprising a timing data of the second main clock CLK_P 2 M, and utilizes the first Bluetooth communication circuit 111 to transmit the second piconet timing packet to the second piconet 320 .
- the first control circuit 114 may utilize various appropriate data to be the timing data of the second main clock CLK_P 2 M.
- the first control circuit 114 may utilize a count value of a specific edge of the second main clock CLK_P 2 M (e.g., the rising edge) to he the timing data of the second main clock CLK_P 2 M, and writes the count value corresponding to the second main clock CLK_P 2 M into a FHS packet so as to form the second piconet timing packet.
- a count value of a specific edge of the second main clock CLK_P 2 M e.g., the rising edge
- the auxiliary Bluetooth circuit 120 is arranged to operably generate a second slave clock CLK_P 2 S 1 according to the timing data of the second main clock CLK_P 2 M, so that the second slave clock CLK_P 2 S 1 is synchronized with the second main clock CLK_P 2 M and utilized to be a slave clock in the second piconet 320 .
- the second Bluetooth communication circuit 121 may receive the second piconet timing packet generated by the main Bluetooth circuit 110 through the second piconet 320 , and the second control circuit 124 may control the second packet parsing circuit 122 to acquire the timing data (such as a relevant count value) of the aforementioned second main clock CLK_P 2 M from the second piconet timing packet.
- the second control circuit 124 is arranged to operably control the second clock adjusting circuit 123 to generate the second slave clock CLK_P 2 S 1 according to the timing data of the first main clock CLK_P 1 M, so that the first slave clock CLK_P 1 S 1 is synchronized with the first main clock CLK_P 1 M.
- the second control circuit 124 may control the second clock adjusting circuit 123 to adjust a frequency and/or a phase offset of a second reference clock CLK_R 2 according to the timing data of the second main clock CLK_P 2 M, so as to generate the second slave clock CLK_P 2 S 1 having a frequency substantially identical to the frequency of the second main clock CLK_P 2 M and a phase substantially aligned with the phase of the second main clock CLK_P 2 M.
- the aforementioned second reference clock CLK_R 2 may be generated by various appropriate clock generating circuits located inside or outside the auxiliary Bluetooth circuit 120 .
- the second control circuit 124 is further arranged to operably control the second clock adjusting circuit 123 to generate a third slave clock CLK_P 1 S 2 according to the timing data of the second main clock CLK_P 2 M, so that the third slave clock CLK_P 1 S 2 is synchronized with the second main clock CLK_P 2 M.
- the second control circuit 124 may control the second clock adjusting circuit 123 to adjust the frequency and/or the phase offset of the aforementioned second reference clock CLK_R 2 according to the timing data of the second main clock CLK_P 2 M, so as to generate the third slave clock CLK_P 1 S 2 having a frequency substantially identical to the frequency of the second main clock CLK_P 2 M and a phase substantially aligned with the phase of the second main clock CLK_P 2 M.
- the auxiliary Bluetooth circuit 120 can utilize the third slave clock CLK_P 1 S 2 to be a slave clock in the first piconet 310 .
- the auxiliary Bluetooth circuit 120 is enabled to sniff the Bluetooth packets in the first piconet 310 without being known by the source Bluetooth device 102 .
- both the second slave clock CLK_P 2 S 1 and the third slave clock CLK_P 1 S 2 . generated by the second clock adjusting circuit 123 are synchronized with the second main clock CLK_P 2 M generated by the main Bluetooth circuit 110 , That is, both the frequency of the second slave clock CLK_P 2 S 1 and the frequency of the third slave clock CLK_P 1 S 2 are substantially identical to the frequency of the second main clock CLK_P 2 M, and both the phase of the second slave clock CLK_P 2 S 1 and the phase of the third slave clock CLK_P 1 S 2 are substantially aligned with the phase of the second main clock CLK_P 2 M.
- the second control circuit 124 may respectively assign different count values to the aforementioned second slave clock CLK_P 2 S 1 and third slave clock CLK_P 1 S 2 .
- the aforementioned method for synchronizing the second slave clock CLK_P 2 S 1 and the third slave clock CLK_P 1 S 2 of the auxiliary Bluetooth circuit 120 can effectively increase the Bluetooth bandwidth utilization efficiency of the auxiliary Bluetooth circuit 120 .
- the second control circuit 124 is arranged to operably control the second Bluetooth communication circuit 121 to schedule the transmission or reception of the Bluetooth packets in the second piconet 320 based on the second slave clock CLK_P 2 S 1 , Additionally, the second control circuit 124 is further arranged to operably schedule the reception of the Bluetooth packets in the first piconet 310 based on the third slave clock CLK_P 1 S 2 so as to sniff the Bluetooth packets in the first piconet 310 .
- the multi-member Bluetooth device 100 in this embodiment can further perform the operation 214 through operation 226 to synchronize the audio playback operation conducted by the main Bluetooth circuit 110 and the audio playback operation conducted by the auxiliary Bluetooth circuit 120 .
- the first control circuit 114 is arranged to operably control the first sampling-clock adjusting circuit 116 to generate a first audio sampling clock CLK_A 1 synchronized with the first main clock CLK_P 1 M, the first slave clock CLK_P 1 S 1 , or the second main clock CLK_P 2 M.
- the first audio sampling clock CLK_A 1 is a clock signal utilized to sample the first audio data stored in the first buffer circuit 115 , thus the frequency of the first audio sampling clock CLK_A 1 is usually lower than the frequency of the first main clock CLK_P 1 M, the frequency of the first slave clock CLK_P 1 S 1 , and the frequency of the second main clock CLK_P 2 M, but the frequency of the first audio sampling clock CLK_A 1 has a fixed ratio relation with the frequency of the first main clock CLK_P 1 M, the frequency of the first slave clock CLK_P 1 S 1 , or the frequency of the second main clock CLK_P 2 M.
- the first control circuit 114 may control the first sampling-clock adjusting circuit 116 to adjust a frequency and/or a phase offset of the first sampling clock CLK_S 1 according to the timing data of the first main clock CLK_P 1 M, so as to generate the first audio sampling clock having a frequency in a predetermined ratio relation with the frequency of the first main clock CLK_P 1 M and a phase substantially aligned with the phase of the first main clock CLK_P 1 M.
- the first control circuit 114 may control the first sampling-clock adjusting circuit 116 to adjust a frequency and/or a phase offset of the first sampling clock CLK_S 1 according to the timing data of the first slave clock CLK_P 1 S 1 , so as to generate the first audio sampling clock CLK_A 1 having a frequency in a predetermined ratio relation with the frequency of the first slave clock CLK_P 1 S 1 and a phase substantially aligned with the phase of the first slave clock CLK_P 1 S 1 .
- the first control circuit 114 may control the first sampling-clock adjusting circuit 116 to adjust a frequency and/or a phase offset of the first sampling clock CLK_S 1 according to the timing data of the second main clock CLK_P 2 M, so as to generate the first audio sampling clock CLK_A 1 having a frequency in a predetermined ratio relation with the frequency of the second main clock CLK_P 2 M and a phase substantially aligned with the phase of the second main clock CLK_P 2 M.
- the aforementioned first sampling clock CLK_S 1 may be generated by various appropriate clock generating circuits located inside or outside the main Bluetooth circuit 110 .
- the first asynchronous sample rate conversion circuit 117 may sample the first audio data stored in the first buffer circuit 115 based on the first audio sampling clock CLK_A 1 under the control of the first control circuit 114 , and then transmit sampled audio data to the first playback circuit 118 for playback.
- the auxiliary Bluetooth circuit 120 may perform the operation 218 and the operation 220 in FIG. 2 .
- the second control circuit 124 is arranged to operably control the second sampling-clock adjusting circuit 126 to generate a second audio sampling clock CLK_A 2 which is not only synchronized with the second main clock CLK_P 2 M, the second slave clock CLK_P 2 S 1 , or the third slave clock CLK_P 1 S 2 , but also has a frequency substantially identical to the frequency of the first audio sampling clock CLK_A 1 .
- the second audio sampling clock CLK_A 2 is a clock signal utilized to sample the second audio data stored in the second buffer circuit 125 , thus the frequency of the second audio sampling clock CLK_A 2 is usually lower than the frequency of the second main clock CLK_P 2 M, the frequency of the second slave clock CLK_P 2 S 1 , and the frequency of the third slave clock CLK_P 1 S 2 , but the frequency of the second audio sampling clock CLK_A 2 has a fixed ratio relation with the frequency of the second main clock CLK_P 2 M, the frequency of the second slave clock CLK_P 2 S 1 , or the frequency of the third slave clock CLK_P 1 S 2 .
- the second control circuit 124 may control the second sampling-clock adjusting circuit 126 to adjust a frequency and/or a phase offset of a second sampling clock CLK_S 2 according to the timing data of the second main clock CLK_P 2 M, so as to generate the second audio sampling clock CLK_A 2 . having a frequency in a predetermined ratio relation with the frequency of the second main clock CLK_P 2 M and a phase substantially aligned with the phase of the second main clock CLK_P 2 M.
- the second control circuit 124 may control the second sampling-clock adjusting circuit 126 to adjust a frequency and/or a phase offset of the second sampling clock CLK_S 2 according to the timing data of the second slave clock CLK_P 2 S 1 , so as to generate the second audio sampling clock CLK_A 2 having a frequency in a predetermined ratio relation with the frequency of the second slave clock CLK_P 2 S 1 and a phase substantially aligned with the phase of the second slave clock CLK_P 2 S 1 .
- the second control circuit 124 may control the second sampling-clock adjusting circuit 126 to adjust a frequency and/or a phase offset of the second sampling dock CLK_S 2 according to the timing data of the third slave clock CLK_P 1 S 2 , so as to generate the second audio sampling clock CLK_A 2 having a frequency in a predetermined ratio relation with the frequency of the third slave clock CLK_P 1 S 2 and a phase substantially aligned with the phase of the third slave clock CLK_P 1 S 2 .
- the aforementioned second sampling clock CLK_S 2 may be generated by various appropriate clock generating circuits located inside or outside the auxiliary Bluetooth circuit 120 .
- the second asynchronous sample rate conversion circuit 127 may sample the second audio data stored in the second buffer circuit 125 based on the second audio sampling clock CLK_A 2 under the control of the second control circuit 124 , and then transmit sampled audio data to the second playback circuit 128 for playback.
- the first audio sampling clock CLK_A 1 generated by the main Bluetooth circuit 110 is synchronized with the first main clock CLK_P 1 M, the first slave clock CLK_P 1 S 1 , or the second main clock CLK_P 2 M, and that the second audio sampling clock CLK_A 2 generated by the auxiliary Bluetooth circuit 120 is synchronized with the second main clock CLK_P 2 M, the second slave clock CLK_P 2 S 1 , or the third slave clock CLK_P 1 S 2 .
- the first main clock CLK_P 1 M, the first slave clock CLK_P 1 S 1 , the second main clock CLK_P 2 M, the second slave clock CLK_P 2 S 1 , and the third slave clock CLK_P 1 S 2 in this embodiment are clock signals substantially synchronized with one another and having a phase substantially aligned with one another
- the first audio sampling clock CLK_A 1 would thus be indirectly synchronized with the second audio sampling clock CLK_A 2
- the phase of the first audio sampling clock CLK_A 1 would be substantially aligned with the phase of the second audio sampling clock CLK_A 2 .
- the audio playback operation conducted by the main Bluetooth circuit 110 and the audio playback operation conducted by the auxiliary Bluetooth circuit 120 can be synchronized with each other without having timing delay issues. Therefore, the aforementioned method for generating the first audio sampling clock CLK_A 1 and the second audio sampling clock CLK_A 2 enables the audio playback operations of different Bluetooth circuits to be synchronized with each other so as to produce ideal stereo sound effects or surround sound effects, and creates positive user experience, thereby increasing the application value and the utilization flexibility of the multi-member Bluetooth device 100 .
- the first audio sampling clock CLK_A 1 of the main Bluetooth circuit 110 is generated directly or indirectly based on the first reference clock CLK_R 1 and the first sampling clock CLK_S 1
- the second audio sampling clock CLK_A 2 of the auxiliary Bluetooth circuit 120 is generated directly or indirectly based on the second reference clock CLK_R 2 and the second sampling clock CLK_S 2 .
- the first reference clock CLK_R 1 adopted by the aforementioned main Bluetooth circuit 110 and the second reference clock CLK_R 2 adopted by the aforementioned auxiliary Bluetooth circuit 120 are two clock signals which are generated independently.
- the first sampling clock CLK_S 1 adopted by the aforementioned the main Bluetooth circuit 110 and the second sampling clock CLK_S 2 adopted by the aforementioned the auxiliary Bluetooth circuit 120 are two clock signals which are generated independently.
- a frequency mismatch phenomenon and/or a phase mismatch phenomenon may be presence between the first audio sampling clock CLK_A 1 of the main Bluetooth circuit 110 and the second audio sampling clock CLK_A 2 of the auxiliary Bluetooth circuit 120 .
- the first audio sampling clock CLK_A 1 of the main Bluetooth circuit 110 and the second audio sampling clock CLK_A 2 of the auxiliary Bluetooth circuit 120 cannot be kept synchronized with each other, it will cause the audio playback operation conducted by the main Bluetooth circuit 110 and the audio playback operation conducted by the auxiliary Bluetooth circuit 120 unable to be kept synchronized with each other, thereby resulting in poor user experience.
- the main Bluetooth circuit 110 intermittently performs the operation 222 during the audio data playback operation
- the auxiliary Bluetooth circuit 120 intermittently performs the operation 224 and the operation 226 during the audio data playback operation.
- the first control circuit 114 transmits a first audio playback time stamp corresponding to the first audio data to the auxiliary Bluetooth circuit 120 through the first Bluetooth communication circuit 111 .
- the first control circuit 114 may utilize a relevant count value of the first audio sampling clock CLK_A 1 (e.g., the count value of the pulse, the count value of the rising edge, the count value of the falling edge, or the like) to be the aforementioned first audio playback time stamp, and transmit the first audio playback time stamp to the auxiliary Bluetooth circuit 120 through the first Bluetooth communication circuit 111 .
- the second control circuit 124 receives the first audio playback time stamp transmitted from the main Bluetooth circuit 110 through the second Bluetooth communication circuit 121 .
- the second control circuit 124 controls the second sampling-clock adjusting circuit 126 to calibrate the phase of the second audio sampling clock CLK_A 2 according to the first audio playback time stamp (e.g., the aforementioned relevant count value), so that the phase of the calibrated second audio sampling clock CLK__A 2 is aligned with the phase of the current first audio sampling clock CLK_A 1 .
- the first audio playback time stamp e.g., the aforementioned relevant count value
- the aforementioned operation 222 through operation 226 it effectively ensures the audio playback operation conducted by the main Bluetooth circuit 110 and the audio playback operation conducted by the auxiliary Bluetooth circuit 120 to be kept synchronized, and prevents timing delay issues.
- the aforementioned method enables playback operation collaboratively performed by the main Bluetooth circuit 110 and the auxiliary Bluetooth circuit 120 to produce ideal stereo sound effects or surround sound effects and create positive user experience, thereby increasing the application value and the utilization flexibility of the multi-member Bluetooth device 100 .
- FIG. 4 shows a simplified flowchart of a method for synchronizing audio playback operations of different Bluetooth circuits according to another embodiment of the present disclosure.
- the operation 202 through operation 220 of FIG. 4 are similar to corresponding operations of the aforementioned embodiment in FIG. 2 , but in the embodiment of FIG. 4 , the approach for synchronizing the audio playback operation conducted by the main Bluetooth circuit 110 and the audio playback operation conducted by the auxiliary Bluetooth circuit 120 is different from the approach adopted in the aforementioned embodiment of FIG. 2 .
- the auxiliary Bluetooth circuit 120 in this embodiment intermittently performs the operation 422 during the audio data playback operation, and the main Bluetooth circuit 110 intermittently performs the operation 424 and the operation 426 during the audio data playback operation.
- the second control circuit 124 transmits a second audio playback time stamp corresponding to the second audio data to the main Bluetooth circuit 110 through the second Bluetooth communication circuit 121 .
- the second control circuit 124 may utilize a relevant count value of the second audio sampling clock CLK_A 2 (e.g., the count value of the pulse, the count value of the rising edge, the count value of the falling edge, or the like) to be the aforementioned second audio playback time stamp, and transmit the second audio playback time stamp to the main Bluetooth circuit 110 through the second Bluetooth communication circuit 121 .
- the first control circuit 114 receives the second audio playback time stamp transmitted from the auxiliary Bluetooth circuit 120 through the first Bluetooth communication circuit 111 .
- the first control circuit 114 controls the first sampling-clock adjusting circuit 116 to calibrate the phase of the first audio sampling clock CLK_A 1 according to the second audio playback time stamp (e.g., the aforementioned relevant count value), so that the phase of the calibrated first audio sampling clock CLK_A 1 is aligned with the phase of the current second audio sampling clock CLK_A 2 .
- the second audio playback time stamp e.g., the aforementioned relevant count value
- the aforementioned operation 422 through operation 426 it effectively ensures the audio playback operation conducted by the main Bluetooth circuit 110 and the audio playback operation conducted by the auxiliary Bluetooth circuit 120 to be kept synchronized, and prevents timing delay issues.
- the aforementioned method enables the playback operation collaboratively performed by the main Bluetooth circuit 110 and the auxiliary Bluetooth circuit 120 to produce ideal stereo sound effects or surround sound effects and create positive user experience, thereby increasing the application value and the utilization flexibility of the multi-member Bluetooth device 100 .
- the main Bluetooth circuit 110 synchronizes both the first slave clock CLK_P 1 S 1 and the second main clock CLK_P 2 M of the main Bluetooth circuit 110 with the first main clock CLK_P 1 M determined by the source Bluetooth device 102 , thus the first clock adjusting circuit 113 can be realized with a simpler circuit structure.
- both the first slave clock CLK_P 1 S 1 and the second main clock CLK_P 2 M adopted by the main Bluetooth circuit 110 are synchronized with the first main clock CLK_P 1 M, which effectively increases the Bluetooth bandwidth utilization efficiency of the main Bluetooth circuit 110 , and also renders the method adopted by the main Bluetooth circuit 110 for updating the first slave clock CLK_P 1 S 1 and the second main clock CLK_P 2 M to be less complicated.
- both the second slave clock CLK_P 2 S 1 and the third slave clock CLK_P 1 S 2 of the auxiliary Bluetooth circuit 120 are synchronized with the second main clock CLK_P 2 M determined by the main Bluetooth circuit 110 , thus the second clock adjusting circuit 123 can be realized with a simpler circuit structure.
- the second slave clock CLK_P 2 S 1 and the third slave clock CLK_P 1 S 2 adopted by the auxiliary Bluetooth circuit 120 are both synchronized with the second main clock CLK_P 2 M, and are both equivalently synchronized with the first main clock CLK_P 1 M, which effectively increases the Bluetooth bandwidth utilization efficiency of the auxiliary Bluetooth circuit 120 , and also renders the method adopted by the auxiliary Bluetooth circuit 120 for updating the second slave clock CLK_P 1 S 1 and the third slave clock CLK_P 1 S 2 to be less complicated.
- the second audio sampling clock CLK_A 2 adopted by the auxiliary Bluetooth circuit 120 can be indirectly synchronized with the first audio sampling clock CLK_A 1 adopted by the main Bluetooth circuit 110 , thus the audio playback operation conducted by the second playback circuit 128 and the audio playback operation conducted by the first playback circuit 118 can be synchronized with each other.
- the quantity of the member circuits in the multi-member Bluetooth device 100 is not limited to two as described in the foregoing embodiments, it may be extended to more quantity depending on the requirement of practical circuit applications.
- the multi-member Bluetooth device 100 may selectively adopt one of the two approaches for synchronizing the audio playback described in the aforementioned embodiments in FIG. 2 and FIG. 4 to ensure the audio playback operation conducted by the main Bluetooth circuit 110 and the audio playback operation conducted by the auxiliary Bluetooth circuit 120 to be kept synchronized.
- the multi-member Bluetooth device 100 may alternately adopt the two approaches to ensure the audio playback operation conducted by the main Bluetooth circuit 110 and the audio playback operation conducted by the auxiliary Bluetooth circuit 120 to be kept synchronized.
- the operation performed by the auxiliary Bluetooth circuit 120 to generate the third slave clock CLK_P 1 S may be omitted.
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Abstract
A multi-member Bluetooth device for communicating data with a source Bluetooth device, wherein the source Bluetooth device acts as a master in a first piconet. The multi-member Bluetooth device includes a main Bluetooth circuit and an auxiliary Bluetooth circuit. The main Bluetooth circuit acts as a slave in the first piconet, and acts as a master in a second piconet. The auxiliary Bluetooth circuit acts as a slave in the second piconet. The main Bluetooth circuit generates a first slave clock and a second main clock synchronized with a first main clock generated by the source Bluetooth device, and samples a first audio data to be playback. The auxiliary Bluetooth circuit generates a second slave clock and a third slave clock synchronized with the second main clock, and samples a second audio data to be playback.
Description
- This application is a Divisional of co-pending U.S. patent application Ser. No. 17/081,652, filed on Oct. 27, 2020, which claims the benefit of priority to Patent Application No. 109133960, filed in Taiwan on Sep. 29, 2020, and also claims the benefit of priority to U.S. Provisional Application Ser. No. 62/930.567, tiled on Nov. 5, 2019; the entirety of which are incorporated herein by reference for all purposes.
- The disclosure generally relates to a Bluetooth technology and, more particularly, to a multi-member Bluetooth device capable of synchronizing audio playback among different Bluetooth circuits.
- A multi-member Bluetooth device is a Bluetooth device formed by multiple Bluetooth circuits cooperating with each other, such as a pair of Bluetooth earphones, a set of Bluetooth speakers, or the like. When the multi-member Bluetooth device connects to another Bluetooth device (hereinafter referred to as a remote Bluetooth device), the remote Bluetooth device treats the multi-member Bluetooth device as a single Bluetooth device.
- Many traditional multi-member Bluetooth devices have playback function. In many applications, different Bluetooth circuits may collaborate to playback audio data to produce stereo sound effects or surround sound effects. However, if the playback operations of different Bluetooth circuits in the multi-member Bluetooth device cannot be synchronized with each other, it would cause terrible user experience, thereby reducing the application value and the utilization flexibility of the multi-member Bluetooth device.
- An example embodiment of a multi-member Bluetooth device utilized to operably conduct data transmission with a source Bluetooth device is disclosed. The source Bluetooth device acts as a master in a first piconet. The multi-member Bluetooth device comprises: a main Bluetooth circuit, comprising: a first Bluetooth communication circuit; a first clock adjusting circuit; a first control circuit, coupled with the first Bluetooth communication circuit and the first clock adjusting circuit, arranged to operably control the main Bluetooth circuit to act as a slave in the first piconet, and to act as a master in a second piconet; a first sampling-clock adjusting circuit, coupled with the first control circuit; and a first asynchronous sample rate conversion circuit, coupled with the first sampling-clock adjusting circuit, arranged to operably sample a first audio data based on a first audio sampling clock, and to operably transmit sampled data to a first playback circuit for playback; and an auxiliary Bluetooth circuit, comprising: a second Bluetooth communication circuit; a second clock adjusting circuit; a second control circuit, coupled with the second. Bluetooth communication circuit and the second clock adjusting circuit, arranged to operably control the auxiliary Bluetooth circuit to act as a slave in the second piconet; a second sampling-clock adjusting circuit, coupled with the second control circuit; and a second asynchronous sample rate conversion circuit, coupled with the second sampling-clock adjusting circuit, arranged to operably sample a second audio data based on a second audio sampling clock, and to operably transmit sampled data to a second playback circuit for playback; wherein the first control circuit is further arranged to operably conduct following operations: controlling the first clock adjusting circuit to generate a first slave clock and a second main clock according to a timing data of a first main clock generated by the source Bluetooth device, so that both the first slave clock and the second main clock are synchronized with the first main clock; and controlling the first Bluetooth communication circuit to transmit or receive packets in the first piconet according to the first slave clock, and controlling the first Bluetooth communication circuit to transmit or receive packets in the second piconet according to the second main clock; wherein the second control circuit is further arranged to operably conduct following operations: controlling the second clock adjusting circuit to generate a second slave clock according to a timing data of the second main clock, so that the second slave clock is synchronized with the second main clock; and controlling the second Bluetooth communication circuit to transmit or receive packets in the second piconet according to the second slave clock.
- Both the foregoing general description and the following detailed description are examples and explanatory only, and are not restrictive of the invention as claimed.
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FIG. 1 shows a simplified functional block diagram of a multi-member Bluetooth device according to one embodiment of the present disclosure. -
FIG. 2 shows a simplified flowchart of a method for synchronizing audio playback operations of different Bluetooth circuits according to one embodiment of the present disclosure. -
FIG. 3 shows a simplified schematic diagram of a scatternet formed by the multi-member Bluetooth device of FIG, 1 according to one embodiment of the present disclosure. -
FIG. 4 shows a simplified flowchart of a method for synchronizing audio playback operations of different Bluetooth circuits according to another embodiment of the present disclosure. - Reference is made in detail to embodiments of the invention, which are illustrated in the accompanying drawings. The same reference numbers may be used throughout the drawings to refer to the same or like parts, components, or operations.
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FIG. 1 shows a simplified functional block diagram of a multi-member Bluetoothdevice 100 according to one embodiment of the present disclosure. The multi-member Bluetoothdevice 100 is arranged to operably conduct data transmission with a source Bluetoothdevice 102, and comprises multiple member circuits. For the convenience of description, only two member circuits are illustrated in the embodiment ofFIG. 1 , which respectively are a main Bluetoothcircuit 110 and an auxiliary Bluetoothcircuit 120. - In this embodiment, all member circuits of the multi-member Bluetooth
device 100 have a similar main circuit structure, but different additional circuit components may be arranged in different member circuits, rather than restricting all member circuits to have an identical circuit structure. As shown inFIG. 1 , for example, themain Bluetooth circuit 110 comprises a first Bluetoothcommunication circuit 111, a firstpacket parsing circuit 112, a firstclock adjusting circuit 113, afirst control circuit 114, afirst buffer circuit 115, a first sampling-clock adjustingcircuit 116, a first asynchronous samplerate conversion circuit 117, and afirst playback circuit 118. Similarly, the auxiliary Bluetoothcircuit 120 comprises a second Bluetoothcommunication circuit 121, a secondpacket parsing circuit 122, a secondclock adjusting circuit 123, a second.control circuit 124, asecond buffer circuit 125, a second sampling-clock adjustingcircuit 126, a second asynchronous samplerate conversion circuit 127, and asecond playback circuit 128. - In the main Bluetooth
circuit 110, the first Bluetoothcommunication circuit 111 is arranged to operably conduct data communication with other Bluetooth devices. The firstpacket parsing circuit 112 is arranged to operably parse packets received by the first Bluetoothcommunication circuit 111. The firstclock adjusting circuit 113 is arranged to operably adjust partial working clock signals adopted by the main Bluetoothcircuit 110 so as to synchronize a piconet clock adopted by the main Bluetoothcircuit 110 and other Bluetooth devices, - The
first control circuit 114 is coupled with the first Bluetoothcommunication circuit 111, the firstpacket parsing circuit 112, and the firstclock adjusting circuit 113, and is arranged to operably control the operations of the aforementioned circuits. In operations, thefirst control circuit 114 may directly conduct data communication with the source Bluetoothdevice 102 through the first Bluetoothcommunication circuit 111 by using a Bluetooth wireless transmission approach, and may conduct data communication with other member circuits through the first Bluetoothcommunication circuit 111. Thefirst control circuit 114 may further utilize the firstpacket parsing circuit 112 to parse the packets received by the first Bluetoothcommunication circuit 111 so as to acquire related data or instructions. - The
first buffer circuit 115 is arranged to operably store audio data for playback (hereinafter referred to as first audio data). In practice, the aforementioned first audio data may be audio data pre-stored in thefirst buffer circuit 115 by the manufacturers or users, audio data transmitted from source Bluetoothdevice 102, audio data transmitted from other Bluetooth circuits (e.g., the auxiliary Bluetooth circuit 120), or audio data transmitted from other circuits. - The first sampling-clock adjusting
circuit 116 is coupled with thefirst control circuit 114, and is arranged to operably generate a first audio sampling clock under control of thefirst control circuit 114. - The first asynchronous sample
rate conversion circuit 117 is coupled with the first sampling-clock adjustingcircuit 116 and thefirst playback circuit 118. The first asynchronous samplerate conversion circuit 117 is arranged to operably sample the first audio data in thefirst buffer circuit 115 based on the first audio sampling clock, and to operably transmit sampled data to thefirst playback circuit 118 for playback. - In the auxiliary Bluetooth
circuit 120, the second Bluetoothcommunication circuit 121 is arranged to operably conduct data communication with other Bluetooth devices. The secondpacket parsing circuit 122 is arranged to operably parse the packets received by the second Bluetoothcommunication circuit 121. The secondclock adjusting circuit 123 is arranged to operably adjust partial working clock signals adopted by the auxiliary Bluetoothcircuit 120 so as to synchronize a piconet clock adopted by the auxiliary Bluetoothcircuit 120 and other Bluetooth devices. - The
second control circuit 124 is coupled with the second Bluetoothcommunication circuit 121, the secondpacket parsing circuit 122, and the secondclock adjusting circuit 123, and is arranged to operably control the operations of the aforementioned circuits. In operations, thesecond control circuit 124 may conduct data communication with other Bluetooth devices through the second Bluetoothcommunication circuit 121 by using the Bluetooth wireless transmission approach, and may conduct data communication with other member circuits through the second Bluetoothcommunication circuit 121. Thesecond control circuit 124 may further utilize the secondpacket parsing circuit 122 to parse the packets received by the second Bluetoothcommunication circuit 121 so as to acquire related data or instructions. - The
second buffer circuit 125 is arranged to operably store audio data for playback (hereinafter referred to as second audio data), in practice, the aforementioned second audio data may be audio data pre-stored in thesecond buffer circuit 125 by the manufacturers or users, audio data transmitted from source Bluetoothdevice 102, audio data transmitted from other Bluetooth circuits (e.g., the main Bluetooth circuit 110), or audio data transmitted from other circuits. - The second sampling-clock adjusting
circuit 126 is coupled with thesecond control circuit 124, and is arranged to operably generate a second audio sampling clock under control of thesecond control circuit 124. - The second asynchronous sample
rate conversion circuit 127 is coupled with the second sampling-clock adjustingcircuit 126 and thesecond playback circuit 128. The second asynchronous samplerate conversion circuit 127 is arranged to operably sample the second audio data in thesecond buffer circuit 125 based on the second audio sampling clock, and to operably transmit sampled data to thesecond playback circuit 128 for playback. - In practice, each of the aforementioned first Bluetooth
communication circuit 111 and second. Bluetoothcommunication circuit 121 may be realized with appropriate wireless communication circuits supporting various versions of Bluetooth communication protocols. Each of the aforementioned firstpacket parsing circuit 112 and the secondpacket parsing circuit 122 may be realized with various packet demodulating circuits, digital processing circuits, micro-processors, or ASICs (Application Specific integrated Circuits). Each of the aforementioned firstclock adjusting circuit 113, secondclock adjusting circuit 123, first sampling-clock adjustingcircuit 116, and the second sampling-clock adjustingcircuit 126 may be realized with various appropriate circuits capable of comparing and adjusting clock frequency and/or clock phase, such as various PLLs (phase-locked loops) or DLLs (delay-locked loops) or the like. Each of the aforementionedfirst control circuit 114 and thesecond control circuit 124 may be realized with various micro-processors or digital signal processing circuits having appropriate computing capability. Each of the aforementionedfirst buffer circuit 115 andsecond buffer circuit 125 may be realized with various volatile memory circuits or non-volatile memory circuits. Each of the aforementioned first asynchronous samplerate conversion circuit 117 and second asynchronous samplerate conversion circuit 127 may be realized with various appropriate digital circuits, analog circuits, or digital/analog hybrid circuits. Each of the aforementionedfirst playback circuit 118 andsecond playback circuit 128 may be realized with various appropriate digital audio playback circuits, analog audio playback circuits, or digital/analog hybrid audio playback circuits. - In some embodiments, the first
clock adjusting circuit 113 or the secondclock adjusting circuit 123 may be respectively integrated into thefirst control circuit 114 or thesecond control circuit 124. The first sampling-clock adjustingcircuit 116 or the second sampling-clock adjustingcircuit 126 may be respectively integrated into thefirst control circuit 114 or thesecond control circuit 124. In addition, the aforementioned firstpacket parsing circuit 112 and the secondpacket parsing circuit 122 may be respectively integrated into the aforementioned first Bluetoothcommunication circuit 111 and second Bluetoothcommunication circuit 121. - In other words, the aforementioned first Bluetooth
communication circuit 111 and firstpacket parsing circuit 112 may be realized with separate circuits, or may be realized with the same circuit. Similarly, the aforementioned secondBluetooth communication circuit 121 and secondpacket parsing circuit 122 may be realized with separate circuits, or may be realized with the same circuit. - In applications, different functional blocks of the aforementioned
main Bluetooth circuit 110 may be integrated into a single circuit chip. For example, all functional blocks of themain Bluetooth circuit 110 or functional blocks except thefirst playback circuit 118 of themain Bluetooth circuit 110 may be integrated into a single Bluetooth controller IC. Similarly, all functional blocks of theauxiliary Bluetooth circuit 120 or functional blocks except thesecond playback circuit 128 of theauxiliary Bluetooth circuit 120 may be integrated into another single Bluetooth controller IC. - In practical applications, the
multi-member Bluetooth device 100 may be realized with a Bluetooth device formed by multiple Bluetooth circuits cooperating with each other, such as a pair of Bluetooth earphones, a set of Bluetooth speakers, or the like. Thesource Bluetooth device 102 may be realized with various electronic apparatuses with Bluetooth communication function such as computers, mobile phones, tablet computers, smart speakers, or game consoles, or the like. - As can be appreciated from the foregoing descriptions, different member circuits of the
multi-member Bluetooth device 100 may conduct data communication with one another through respective Bluetooth communication circuits, so as to form various types of Bluetooth network. When themulti-member Bluetooth device 100 conducts data communication with thesource Bluetooth device 102, thesource Bluetooth device 102 treats themulti-member Bluetooth device 100 as a single Bluetooth device. - The
main Bluetooth circuit 110 may adopt various existing mechanisms to receive the packets issued from thesource Bluetooth device 102, and during the operation of themain Bluetooth circuit 110, theauxiliary Bluetooth circuit 120 may acquire the packets issued from thesource Bluetooth device 102 by adopting appropriate mechanisms. - For example, in a period during which the
main Bluetooth circuit 110 receives the packets issued from thesource Bluetooth device 102, theauxiliary Bluetooth circuit 120 may operate at a sniffing mode to actively sniff the packets issued from thesource Bluetooth device 102. Alternatively, theauxiliary Bluetooth circuit 120 may operate at a relay mode to passively receive the packets forwarded from themain Bluetooth circuit 110 after the packets issued from thesource Bluetooth device 102 are received by themain Bluetooth circuit 110, and theauxiliary Bluetooth circuit 120 does not actively sniff the packets issued from thesource Bluetooth device 102. - Please note that two terms “main Bluetooth circuit” and “auxiliary Bluetooth circuit” used throughout the description and claims are merely for the purpose of distinguishing different approaches of receiving packets issued from the
source Bluetooth device 102 adopted by different member circuits, rather than indicating that themain Bluetooth circuit 110 is required to have a specific level of control authority over other operational aspects of theauxiliary Bluetooth circuit 120. In practice, themain Bluetooth circuit 110 and theauxiliary Bluetooth circuit 120 may exchange their roles with each other intermittently, periodically, or in situations where specific conditions are matched. - The operations of the
multi-member Bluetooth device 100 will be further described in the following by reference to FIG, 2 throughFIG. 3 .FIG. 2 shows a simplified flowchart of a method for synchronizing audio playback operations of different Bluetooth circuits according to one embodiment of the present disclosure.FIG. 3 shows a simplified schematic diagram of a scatternet formed by themulti-member Bluetooth device 100 according to one embodiment of the present disclosure. - In the flowchart of
FIG. 2 , operations within a column under the name of a specific device are operations to be performed by the specific device. For example, operations within a column under the label “source Bluetooth device” are operations to be performed by thesource Bluetooth device 102; operations within a column under the label “main Bluetooth circuit” are operations to be performed by themain Bluetooth circuit 110; operations within a column under the label “auxiliary Bluetooth circuit” are operations to be performed by theauxiliary Bluetooth circuit 120. The same analogous arrangement also applies to the subsequent flowcharts. - As shown in
FIG. 2 , themain Bluetooth circuit 110 of themulti-member Bluetooth device 100 performs theoperation 202 with thesource Bluetooth device 102 so as to utilize various methods complying with Bluetooth communication protocols to form afirst piconet 310 as shown inFIG. 3 . In theoperation 202, thesource Bluetooth device 102 acts as a master in thefirst piconet 310, and themain Bluetooth circuit 110 of themulti-member Bluetooth device 100 acts as a slave in thefirst piconet 310. - In the
operation 204, thesource Bluetooth device 102 generates a first main clock CLK_P1M, and schedules the transmission or reception of Bluetooth packets in thefirst piconet 310 based on the first main clock CLK_P1M, Therefore, the first main clock CLK_P1M is not only a native system clock of thesource Bluetooth device 102 but also a master clock of thefirst piconet 310 simultaneously. - Additionally, the
source Bluetooth device 102 generates and transmits a first piconet timing packet comprising a timing data of the first main clock CLK_P1M to thefirst piconet 310. In practice, thesource Bluetooth device 102 may utilize various appropriate data to be the timing data of the first main clock CLK_P1M. For example, thesource Bluetooth device 102 may utilize a count value of a specific edge of the first main clock CLK_P1M (e.g., the rising edge) to be the timing data of the first main clock CLK_P1M, and writes the count value corresponding to the first main clock CLK_P1M into a FHS packet (frequency hop synchronization packet) so as to form the first piconet timing packet. - In the
operation 206, themain Bluetooth circuit 110 is arranged to operably generate a first slave clock CLK_P1S1 according to the timing data of the first main clock CLK_P1M, so that the first slave clock CLK_P1S1 is synchronized with the first main clock CLK_P1M and utilized to be a slave clock in thefirst piconet 310. In practice, the firstBluetooth communication circuit 111 may receive the first piconet timing packet generated by thesource Bluetooth device 102 through thefirst piconet 310, thefirst control circuit 114 may control the firstpacket parsing circuit 112 to acquire the timing data (such as a relevant count value) of the aforementioned first main clock CLK_P1M from the first piconet timing packet, - Next, the
first control circuit 114 is arranged to operably control the firstclock adjusting circuit 113 to generate a first slave clock CLK_P1S1 according to the timing data of the first main clock CLK_P1M, so that the first slave clock CLK_P1S1 is synchronized with the first main clock CLK_P1M. For example, thefirst control circuit 114 may control the firstclock adjusting circuit 113 to adjust a frequency and/or a phase offset of a first reference clock CLK_R1 according to the timing data of the first main clock CLK_P1M, so as to generate the first slave clock CLK_P1S1 having a frequency substantially identical to the frequency of the first main clock CLK_P1M and a phase substantially aligned with the phase of the first main clock CLK_P1M. In practice, the aforementioned first reference clock CLK_R1 may be generated by various appropriate clock generating circuits located inside or outside themain Bluetooth circuit 110. - In operations, the
first control circuit 114 is arranged to operably control the firstBluetooth communication circuit 111 to schedule the transmission or reception of the Bluetooth packets in thefirst piconet 310 based on the first slave clock CLK_P1S1. - In the
operation 208, themain Bluetooth circuit 110 and theauxiliary Bluetooth circuit 120 of themulti-member Bluetooth device 100 may utilize various methods complying with Bluetooth communication protocols to form asecond piconet 320 as shown inFIG. 3 . In this embodiment, themain Bluetooth circuit 110 acts as the master in thesecond piconet 320, and theauxiliary Bluetooth circuit 120 acts as the slave in thesecond piconet 320. - In other words, the
main Bluetooth circuit 110 is not only a member of the aforementionedfirst piconet 310 but also a member of thesecond piconet 320 simultaneously. - In the
operation 210, thefirst control circuit 114 is arranged to operably control the firstclock adjusting circuit 113 to generate a second main clock CLK_P2M according to the timing data of the first main clock CLK_P1M or the timing data of the first slave clock CLK_P1S1, so that the second main clock CLK_P2M is synchronized with the first main clock CLK_P1M. For example, thefirst control circuit 114 may control the firstclock adjusting circuit 113 to adjust the frequency and/or the phase offset of the aforementioned first reference clock CLK_R1 according to the timing data of the first main clock CLK_P1M or the timing data of the first slave clock CLK_P1S1 so as to generate the second main clock CLK_P2M having a frequency substantially identical to the frequency of the first main clock CLK_P1M and a phase substantially aligned with the phase of the first main clock CLK_P1M. - In operations, the
first control circuit 114 is arranged to operably control the firstBluetooth communication circuit 111 to schedule the transmission or reception of the Bluetooth packets in thesecond piconet 320 based on the second main clock CLK_P2M. Therefore, the second main clock CLK_P2M is not only the native system clock of themain Bluetooth circuit 110 but also the master clock in thesecond piconet 320 simultaneously. - As can be appreciated from the foregoing descriptions, both the first slave clock CLK_P1S1 and the second main clock CLK_P2M generated by the first
clock adjusting circuit 113 are synchronized with the first main clock CLK_P1M generated by thesource Bluetooth device 102. That is, both the frequency of the first slave clock CLK_P1S1 and the frequency of the second main clock CLK_P2M are substantially identical to the frequency of the first main clock CLK_P1M, and both the phase of the first slave clock CLK_P1S1 and the phase of the second main clock CLK_P2M are substantially aligned with the phase of the first main clock CLK_P1M. - In practice, the
first control circuit 114 may respectively assign different count values to the aforementioned first slave clock CLK_P1S1 and second main clock CLK_P2M. - The aforementioned method for synchronizing the first slave clock CLK_P1S1 and the second main clock CLK_P2M of the
main Bluetooth circuit 110 can effectively increase the Bluetooth bandwidth utilization efficiency of themain Bluetooth circuit 110. - Additionally, in the
aforementioned operation 210, thefirst control circuit 114 is further arranged to operably generate a second piconet timing packet comprising a timing data of the second main clock CLK_P2M, and utilizes the firstBluetooth communication circuit 111 to transmit the second piconet timing packet to thesecond piconet 320. In practice, thefirst control circuit 114 may utilize various appropriate data to be the timing data of the second main clock CLK_P2M. For example, thefirst control circuit 114 may utilize a count value of a specific edge of the second main clock CLK_P2M (e.g., the rising edge) to he the timing data of the second main clock CLK_P2M, and writes the count value corresponding to the second main clock CLK_P2M into a FHS packet so as to form the second piconet timing packet. - In the
operation 212, theauxiliary Bluetooth circuit 120 is arranged to operably generate a second slave clock CLK_P2S1 according to the timing data of the second main clock CLK_P2M, so that the second slave clock CLK_P2S1 is synchronized with the second main clock CLK_P2M and utilized to be a slave clock in thesecond piconet 320. In practice, the secondBluetooth communication circuit 121 may receive the second piconet timing packet generated by themain Bluetooth circuit 110 through thesecond piconet 320, and thesecond control circuit 124 may control the secondpacket parsing circuit 122 to acquire the timing data (such as a relevant count value) of the aforementioned second main clock CLK_P2M from the second piconet timing packet. - Next, the
second control circuit 124 is arranged to operably control the secondclock adjusting circuit 123 to generate the second slave clock CLK_P2S1 according to the timing data of the first main clock CLK_P1M, so that the first slave clock CLK_P1S1 is synchronized with the first main clock CLK_P1M. For example, thesecond control circuit 124 may control the secondclock adjusting circuit 123 to adjust a frequency and/or a phase offset of a second reference clock CLK_R2 according to the timing data of the second main clock CLK_P2M, so as to generate the second slave clock CLK_P2S1 having a frequency substantially identical to the frequency of the second main clock CLK_P2M and a phase substantially aligned with the phase of the second main clock CLK_P2M. In practice, the aforementioned second reference clock CLK_R2 may be generated by various appropriate clock generating circuits located inside or outside theauxiliary Bluetooth circuit 120. - Additionally, in the
operation 212, thesecond control circuit 124 is further arranged to operably control the secondclock adjusting circuit 123 to generate a third slave clock CLK_P1S2 according to the timing data of the second main clock CLK_P2M, so that the third slave clock CLK_P1S2 is synchronized with the second main clock CLK_P2M. For example, thesecond control circuit 124 may control the secondclock adjusting circuit 123 to adjust the frequency and/or the phase offset of the aforementioned second reference clock CLK_R2 according to the timing data of the second main clock CLK_P2M, so as to generate the third slave clock CLK_P1S2 having a frequency substantially identical to the frequency of the second main clock CLK_P2M and a phase substantially aligned with the phase of the second main clock CLK_P2M. - Since the second main clock CLK_P2M generated by the
main Bluetooth circuit 110 is synchronized with the first main clock CLK_P1M generated by thesource Bluetooth device 102, the aforementioned third slave clock CLK_P1S2 generated by the secondclock adjusting circuit 123 is indirectly synchronized with the first main clock CLK_P1M generated by thesource Bluetooth device 102, thus theauxiliary Bluetooth circuit 120 can utilize the third slave clock CLK_P1S2 to be a slave clock in thefirst piconet 310. In this way, theauxiliary Bluetooth circuit 120 is enabled to sniff the Bluetooth packets in thefirst piconet 310 without being known by thesource Bluetooth device 102. - As can be appreciated from the foregoing descriptions, both the second slave clock CLK_P2S1 and the third slave clock CLK_P1S2. generated by the second
clock adjusting circuit 123 are synchronized with the second main clock CLK_P2M generated by themain Bluetooth circuit 110, That is, both the frequency of the second slave clock CLK_P2S1 and the frequency of the third slave clock CLK_P1S2 are substantially identical to the frequency of the second main clock CLK_P2M, and both the phase of the second slave clock CLK_P2S1 and the phase of the third slave clock CLK_P1S2 are substantially aligned with the phase of the second main clock CLK_P2M. - In practice, the
second control circuit 124 may respectively assign different count values to the aforementioned second slave clock CLK_P2S1 and third slave clock CLK_P1S2. - The aforementioned method for synchronizing the second slave clock CLK_P2S1 and the third slave clock CLK_P1S2 of the
auxiliary Bluetooth circuit 120 can effectively increase the Bluetooth bandwidth utilization efficiency of theauxiliary Bluetooth circuit 120. - Afterwards, the
second control circuit 124 is arranged to operably control the secondBluetooth communication circuit 121 to schedule the transmission or reception of the Bluetooth packets in thesecond piconet 320 based on the second slave clock CLK_P2S1, Additionally, thesecond control circuit 124 is further arranged to operably schedule the reception of the Bluetooth packets in thefirst piconet 310 based on the third slave clock CLK_P1S2 so as to sniff the Bluetooth packets in thefirst piconet 310. - As shown in
FIG. 2 , themulti-member Bluetooth device 100 in this embodiment can further perform theoperation 214 throughoperation 226 to synchronize the audio playback operation conducted by themain Bluetooth circuit 110 and the audio playback operation conducted by theauxiliary Bluetooth circuit 120. - in the
operation 214, thefirst control circuit 114 is arranged to operably control the first sampling-clock adjusting circuit 116 to generate a first audio sampling clock CLK_A1 synchronized with the first main clock CLK_P1M, the first slave clock CLK_P1S1, or the second main clock CLK_P2M. In this embodiment, the first audio sampling clock CLK_A1 is a clock signal utilized to sample the first audio data stored in thefirst buffer circuit 115, thus the frequency of the first audio sampling clock CLK_A1 is usually lower than the frequency of the first main clock CLK_P1M, the frequency of the first slave clock CLK_P1S1, and the frequency of the second main clock CLK_P2M, but the frequency of the first audio sampling clock CLK_A1 has a fixed ratio relation with the frequency of the first main clock CLK_P1M, the frequency of the first slave clock CLK_P1S1, or the frequency of the second main clock CLK_P2M. - For example, the
first control circuit 114 may control the first sampling-clock adjusting circuit 116 to adjust a frequency and/or a phase offset of the first sampling clock CLK_S1 according to the timing data of the first main clock CLK_P1M, so as to generate the first audio sampling clock having a frequency in a predetermined ratio relation with the frequency of the first main clock CLK_P1M and a phase substantially aligned with the phase of the first main clock CLK_P1M. - For another example, the
first control circuit 114 may control the first sampling-clock adjusting circuit 116 to adjust a frequency and/or a phase offset of the first sampling clock CLK_S1 according to the timing data of the first slave clock CLK_P1S1, so as to generate the first audio sampling clock CLK_A1 having a frequency in a predetermined ratio relation with the frequency of the first slave clock CLK_P1S1 and a phase substantially aligned with the phase of the first slave clock CLK_P1S1. - For another example, the
first control circuit 114 may control the first sampling-clock adjusting circuit 116 to adjust a frequency and/or a phase offset of the first sampling clock CLK_S1 according to the timing data of the second main clock CLK_P2M, so as to generate the first audio sampling clock CLK_A1 having a frequency in a predetermined ratio relation with the frequency of the second main clock CLK_P2M and a phase substantially aligned with the phase of the second main clock CLK_P2M. - In practice, the aforementioned first sampling clock CLK_S1 may be generated by various appropriate clock generating circuits located inside or outside the
main Bluetooth circuit 110. - In the
operation 216, the first asynchronous samplerate conversion circuit 117 may sample the first audio data stored in thefirst buffer circuit 115 based on the first audio sampling clock CLK_A1 under the control of thefirst control circuit 114, and then transmit sampled audio data to thefirst playback circuit 118 for playback. - On the other hand, the
auxiliary Bluetooth circuit 120 may perform theoperation 218 and theoperation 220 inFIG. 2 . - In the
operation 218, thesecond control circuit 124 is arranged to operably control the second sampling-clock adjusting circuit 126 to generate a second audio sampling clock CLK_A2 which is not only synchronized with the second main clock CLK_P2M, the second slave clock CLK_P2S1, or the third slave clock CLK_P1S2, but also has a frequency substantially identical to the frequency of the first audio sampling clock CLK_A1. In this embodiment, the second audio sampling clock CLK_A2 is a clock signal utilized to sample the second audio data stored in thesecond buffer circuit 125, thus the frequency of the second audio sampling clock CLK_A2 is usually lower than the frequency of the second main clock CLK_P2M, the frequency of the second slave clock CLK_P2S1, and the frequency of the third slave clock CLK_P1S2, but the frequency of the second audio sampling clock CLK_A2 has a fixed ratio relation with the frequency of the second main clock CLK_P2M, the frequency of the second slave clock CLK_P2S1, or the frequency of the third slave clock CLK_P1S2. - For example, the
second control circuit 124 may control the second sampling-clock adjusting circuit 126 to adjust a frequency and/or a phase offset of a second sampling clock CLK_S2 according to the timing data of the second main clock CLK_P2M, so as to generate the second audio sampling clock CLK_A2. having a frequency in a predetermined ratio relation with the frequency of the second main clock CLK_P2M and a phase substantially aligned with the phase of the second main clock CLK_P2M. - For another example, the
second control circuit 124 may control the second sampling-clock adjusting circuit 126 to adjust a frequency and/or a phase offset of the second sampling clock CLK_S2 according to the timing data of the second slave clock CLK_P2S1, so as to generate the second audio sampling clock CLK_A2 having a frequency in a predetermined ratio relation with the frequency of the second slave clock CLK_P2S1 and a phase substantially aligned with the phase of the second slave clock CLK_P2S1. - For another example, the
second control circuit 124 may control the second sampling-clock adjusting circuit 126 to adjust a frequency and/or a phase offset of the second sampling dock CLK_S2 according to the timing data of the third slave clock CLK_P1S2, so as to generate the second audio sampling clock CLK_A2 having a frequency in a predetermined ratio relation with the frequency of the third slave clock CLK_P1S2 and a phase substantially aligned with the phase of the third slave clock CLK_P1S2. - In practice, the aforementioned second sampling clock CLK_S2 may be generated by various appropriate clock generating circuits located inside or outside the
auxiliary Bluetooth circuit 120. - In the
operation 220, the second asynchronous samplerate conversion circuit 127 may sample the second audio data stored in thesecond buffer circuit 125 based on the second audio sampling clock CLK_A2 under the control of thesecond control circuit 124, and then transmit sampled audio data to thesecond playback circuit 128 for playback. - As can be appreciated from the foregoing descriptions, the first audio sampling clock CLK_A1 generated by the
main Bluetooth circuit 110 is synchronized with the first main clock CLK_P1M, the first slave clock CLK_P1S1, or the second main clock CLK_P2M, and that the second audio sampling clock CLK_A2 generated by theauxiliary Bluetooth circuit 120 is synchronized with the second main clock CLK_P2M, the second slave clock CLK_P2S1, or the third slave clock CLK_P1S2. Since the first main clock CLK_P1M, the first slave clock CLK_P1S1, the second main clock CLK_P2M, the second slave clock CLK_P2S1, and the third slave clock CLK_P1S2 in this embodiment are clock signals substantially synchronized with one another and having a phase substantially aligned with one another, the first audio sampling clock CLK_A1 would thus be indirectly synchronized with the second audio sampling clock CLK_A2, and the phase of the first audio sampling clock CLK_A1 would be substantially aligned with the phase of the second audio sampling clock CLK_A2. - As a result, the audio playback operation conducted by the
main Bluetooth circuit 110 and the audio playback operation conducted by theauxiliary Bluetooth circuit 120 can be synchronized with each other without having timing delay issues. Therefore, the aforementioned method for generating the first audio sampling clock CLK_A1 and the second audio sampling clock CLK_A2 enables the audio playback operations of different Bluetooth circuits to be synchronized with each other so as to produce ideal stereo sound effects or surround sound effects, and creates positive user experience, thereby increasing the application value and the utilization flexibility of themulti-member Bluetooth device 100. - As can be appreciated from the foregoing descriptions, the first audio sampling clock CLK_A1 of the
main Bluetooth circuit 110 is generated directly or indirectly based on the first reference clock CLK_R1 and the first sampling clock CLK_S1, and the second audio sampling clock CLK_A2 of theauxiliary Bluetooth circuit 120 is generated directly or indirectly based on the second reference clock CLK_R2 and the second sampling clock CLK_S2. - In general, the first reference clock CLK_R1 adopted by the aforementioned
main Bluetooth circuit 110 and the second reference clock CLK_R2 adopted by the aforementionedauxiliary Bluetooth circuit 120 are two clock signals which are generated independently. Additionally, the first sampling clock CLK_S1 adopted by the aforementioned themain Bluetooth circuit 110 and the second sampling clock CLK_S2 adopted by the aforementioned theauxiliary Bluetooth circuit 120 are two clock signals which are generated independently. - Accordingly, after the
main Bluetooth circuit 110 and theauxiliary Bluetooth circuit 120 synchronously conduct audio playback operations for a certain period of time, it is possible that a frequency mismatch phenomenon and/or a phase mismatch phenomenon may be presence between the first audio sampling clock CLK_A1 of themain Bluetooth circuit 110 and the second audio sampling clock CLK_A2 of theauxiliary Bluetooth circuit 120. - If the first audio sampling clock CLK_A1 of the
main Bluetooth circuit 110 and the second audio sampling clock CLK_A2 of theauxiliary Bluetooth circuit 120 cannot be kept synchronized with each other, it will cause the audio playback operation conducted by themain Bluetooth circuit 110 and the audio playback operation conducted by theauxiliary Bluetooth circuit 120 unable to be kept synchronized with each other, thereby resulting in poor user experience. - Therefore, in this embodiment, the
main Bluetooth circuit 110 intermittently performs theoperation 222 during the audio data playback operation, and theauxiliary Bluetooth circuit 120 intermittently performs theoperation 224 and theoperation 226 during the audio data playback operation. - In the
operation 222, thefirst control circuit 114 transmits a first audio playback time stamp corresponding to the first audio data to theauxiliary Bluetooth circuit 120 through the firstBluetooth communication circuit 111. In practice, thefirst control circuit 114 may utilize a relevant count value of the first audio sampling clock CLK_A1 (e.g., the count value of the pulse, the count value of the rising edge, the count value of the falling edge, or the like) to be the aforementioned first audio playback time stamp, and transmit the first audio playback time stamp to theauxiliary Bluetooth circuit 120 through the firstBluetooth communication circuit 111. - In the
operation 224, thesecond control circuit 124 receives the first audio playback time stamp transmitted from themain Bluetooth circuit 110 through the secondBluetooth communication circuit 121. - In the
operation 226, thesecond control circuit 124 controls the second sampling-clock adjusting circuit 126 to calibrate the phase of the second audio sampling clock CLK_A2 according to the first audio playback time stamp (e.g., the aforementioned relevant count value), so that the phase of the calibrated second audio sampling clock CLK__A2 is aligned with the phase of the current first audio sampling clock CLK_A1. - Accordingly, by performing the
aforementioned operation 222 throughoperation 226, it effectively ensures the audio playback operation conducted by themain Bluetooth circuit 110 and the audio playback operation conducted by theauxiliary Bluetooth circuit 120 to be kept synchronized, and prevents timing delay issues. As a result, the aforementioned method enables playback operation collaboratively performed by themain Bluetooth circuit 110 and theauxiliary Bluetooth circuit 120 to produce ideal stereo sound effects or surround sound effects and create positive user experience, thereby increasing the application value and the utilization flexibility of themulti-member Bluetooth device 100. - Please refer to
FIG. 4 , which shows a simplified flowchart of a method for synchronizing audio playback operations of different Bluetooth circuits according to another embodiment of the present disclosure. - The
operation 202 throughoperation 220 ofFIG. 4 are similar to corresponding operations of the aforementioned embodiment inFIG. 2 , but in the embodiment ofFIG. 4 , the approach for synchronizing the audio playback operation conducted by themain Bluetooth circuit 110 and the audio playback operation conducted by theauxiliary Bluetooth circuit 120 is different from the approach adopted in the aforementioned embodiment ofFIG. 2 . - As shown in
FIG. 4 , theauxiliary Bluetooth circuit 120 in this embodiment intermittently performs theoperation 422 during the audio data playback operation, and themain Bluetooth circuit 110 intermittently performs theoperation 424 and theoperation 426 during the audio data playback operation. - In the
operation 422, thesecond control circuit 124 transmits a second audio playback time stamp corresponding to the second audio data to themain Bluetooth circuit 110 through the secondBluetooth communication circuit 121. In practice, thesecond control circuit 124 may utilize a relevant count value of the second audio sampling clock CLK_A2 (e.g., the count value of the pulse, the count value of the rising edge, the count value of the falling edge, or the like) to be the aforementioned second audio playback time stamp, and transmit the second audio playback time stamp to themain Bluetooth circuit 110 through the secondBluetooth communication circuit 121. - In the
operation 424, thefirst control circuit 114 receives the second audio playback time stamp transmitted from theauxiliary Bluetooth circuit 120 through the firstBluetooth communication circuit 111. - In the
operation 426, thefirst control circuit 114 controls the first sampling-clock adjusting circuit 116 to calibrate the phase of the first audio sampling clock CLK_A1 according to the second audio playback time stamp (e.g., the aforementioned relevant count value), so that the phase of the calibrated first audio sampling clock CLK_A1 is aligned with the phase of the current second audio sampling clock CLK_A2. - Accordingly, by performing the
aforementioned operation 422 throughoperation 426, it effectively ensures the audio playback operation conducted by themain Bluetooth circuit 110 and the audio playback operation conducted by theauxiliary Bluetooth circuit 120 to be kept synchronized, and prevents timing delay issues. As a result, the aforementioned method enables the playback operation collaboratively performed by themain Bluetooth circuit 110 and theauxiliary Bluetooth circuit 120 to produce ideal stereo sound effects or surround sound effects and create positive user experience, thereby increasing the application value and the utilization flexibility of themulti-member Bluetooth device 100. - In the aforementioned
multi-member Bluetooth device 100, themain Bluetooth circuit 110 synchronizes both the first slave clock CLK_P1S1 and the second main clock CLK_P2M of themain Bluetooth circuit 110 with the first main clock CLK_P1M determined by thesource Bluetooth device 102, thus the firstclock adjusting circuit 113 can be realized with a simpler circuit structure. - Additionally, both the first slave clock CLK_P1S1 and the second main clock CLK_P2M adopted by the
main Bluetooth circuit 110 are synchronized with the first main clock CLK_P1M, which effectively increases the Bluetooth bandwidth utilization efficiency of themain Bluetooth circuit 110, and also renders the method adopted by themain Bluetooth circuit 110 for updating the first slave clock CLK_P1S1 and the second main clock CLK_P2M to be less complicated. - Similarly, both the second slave clock CLK_P2S1 and the third slave clock CLK_P1S2 of the
auxiliary Bluetooth circuit 120 are synchronized with the second main clock CLK_P2M determined by themain Bluetooth circuit 110, thus the secondclock adjusting circuit 123 can be realized with a simpler circuit structure. - Moreover, the second slave clock CLK_P2S1 and the third slave clock CLK_P1S2 adopted by the
auxiliary Bluetooth circuit 120 are both synchronized with the second main clock CLK_P2M, and are both equivalently synchronized with the first main clock CLK_P1M, which effectively increases the Bluetooth bandwidth utilization efficiency of theauxiliary Bluetooth circuit 120, and also renders the method adopted by theauxiliary Bluetooth circuit 120 for updating the second slave clock CLK_P1S1 and the third slave clock CLK_P1S2 to be less complicated. - More importantly, the second audio sampling clock CLK_A2 adopted by the
auxiliary Bluetooth circuit 120 can be indirectly synchronized with the first audio sampling clock CLK_A1 adopted by themain Bluetooth circuit 110, thus the audio playback operation conducted by thesecond playback circuit 128 and the audio playback operation conducted by thefirst playback circuit 118 can be synchronized with each other. - Please note that the quantity of the member circuits in the
multi-member Bluetooth device 100 is not limited to two as described in the foregoing embodiments, it may be extended to more quantity depending on the requirement of practical circuit applications. - In practice, the
multi-member Bluetooth device 100 may selectively adopt one of the two approaches for synchronizing the audio playback described in the aforementioned embodiments inFIG. 2 andFIG. 4 to ensure the audio playback operation conducted by themain Bluetooth circuit 110 and the audio playback operation conducted by theauxiliary Bluetooth circuit 120 to be kept synchronized. Alternatively, themulti-member Bluetooth device 100 may alternately adopt the two approaches to ensure the audio playback operation conducted by themain Bluetooth circuit 110 and the audio playback operation conducted by theauxiliary Bluetooth circuit 120 to be kept synchronized. - Additionally, in some applications, the operation performed by the
auxiliary Bluetooth circuit 120 to generate the third slave clock CLK_P1S may be omitted. - Certain terms are used throughout the description and the claims to refer to particular components. One skilled in the art appreciates that a component may be referred to as different names. This disclosure does not intend to distinguish between components that differ in name but not in function. In the description and in the claims, the term “comprise” is used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to.” The term “couple” is intended to compass any indirect or direct connection. Accordingly, if this disclosure mentioned that a first device is coupled with a second device, it means that the first device may be directly or indirectly connected to the second device through electrical connections, wireless communications, optical communications, or other signal connections with/without other intermediate devices or connection means.
- The term “and/or” may comprise any and all combinations of one or more of the associated listed items. In addition, the singular forms “a,” “an,” and “the” herein are intended to comprise the plural forms as well, unless the context clearly indicates otherwise.
- Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention indicated by the following claims.
Claims (6)
1. A multi-member Bluetooth device (100) utilized to operably conduct data transmission with a source Bluetooth device (102) where the source Bluetooth device (102) being acting as a master in a first piconet (310), the multi-member Bluetooth device (100) comprising:
a main Bluetooth circuit (110), comprising:
a first Bluetooth communication circuit (111);
a first clock adjusting circuit (113);
a first control circuit (114), coupled with the first Bluetooth communication circuit (111) and the first clock adjusting circuit (113), arranged to operably control the main Bluetooth circuit (110) to act as a slave in the first piconet (310), and to act as a master in a second piconet (320);
a first sampling-clock adjusting circuit (116), coupled with e first control circuit (114); and
a first asynchronous sample rate conversion circuit (117), coupled with the first sampling-clock adjusting circuit (116), arranged to operably sample a first audio data based on a first audio sampling clock (CLK_A1), and to operably transmit sampled data to a first playback circuit (118) for playback; and
an auxiliary Bluetooth circuit (120), comprising:
a second Bluetooth communication circuit (121);
a second clock adjusting circuit (123);
a second control circuit (124), coupled with the second Bluetooth communication circuit (121) and the second clock adjusting circuit (123), arranged to operably control the auxiliary Bluetooth circuit (120) to act as a slave in the second piconet (320);
a second sampling-clock adjusting circuit (126), coupled with the second control circuit (124); and
a second asynchronous sample rate conversion circuit (127), coupled with the second sampling-clock adjusting circuit (126), arranged to operably sample a second audio data based on a second audio sampling clock (CLK_A2), and to operably transmit sampled data to a second playback circuit (128) for playback;
wherein the first control circuit (114) is further arranged to operably conduct following operations:
controlling the first clock adjusting circuit (113) to generate a first slave clock (CLK_P1S1) and a second main clock (CLK_P2M) according to a timing data of a first main clock (CLK_P1M) generated by the source Bluetooth device (102), so that both the first slave clock (CLK_S1) and the second main clock (CLK_P2M) are synchronized with the first main clock (CLK_P1M); and
controlling the first Bluetooth communication circuit (111) to transmit or receive packets in the first piconet (310) according to the first slave clock (CLK_P1S1), and controlling the first Bluetooth communication circuit (111) to transmit or receive packets in the second piconet (320) according to the second main clock (CLK_P2M);
wherein the second control circuit (124) is further arranged to operably conduct following operations:
controlling the second clock adjusting circuit (123) to generate a second slave clock (CLK_P2S1) according to a timing data of the second main clock (CLK_P2M), so that the second slave clock (CLK_P2S1) is synchronized with the second main clock (CLK_P2M); and
controlling the second Bluetooth communication circuit (121) to transmit or receive packets in the second piconet (320) according to the second slave dock (CLK_P2S1).
2. The multi-member Bluetooth device (100) of claim 1 , wherein the first control circuit (114) is further arranged to operably control the first sampling-clock adjusting circuit (116) to generate the first audio sampling clock (CLK_A1) synchronized with the first main clock (CLK_P1M), the first slave clock (CLK_P1S1), or the second main clock (CLK_P2M), and the second control circuit (124′ is further arranged to operably control the second sampling-clock adjusting circuit (126) to generate the second audio sampling clock (CLK_A2) synchronized with the second main clock (CLK_P2M) or the second slave clock (CLK_P2S1), so that the second audio sampling clock (CLK_A2) is indirectly synchronized with the first audio sampling clock (CLK_A1).
3. The multi-member Bluetooth device (100) of claim 2 , wherein the first control circuit (114) is further arranged to operably transmit a corresponding first audio playback time stamp of the first audio data to the auxiliary Bluetooth circuit (120) through the first Bluetooth communication circuit (111), and the second control circuit (124) is further arranged to operably receive the first audio playback time stamp through the second Bluetooth communication circuit (121), and to operably control the second sampling-clock adjusting circuit (126) to calibrate a phase of the second audio sampling clock (CLK_A2) according to the first audio playback time stamp, so that a calibrated second audio sampling clock (CLK_A2) is synchronized with a current first audio sampling clock (CLK_A1).
4. The multi-member Bluetooth device (100) of claim 2 , wherein the second control circuit (124) is further arranged to operably transmit a corresponding second audio playback time stamp of the second audio data to the main Bluetooth circuit (110) through the second Bluetooth communication circuit (121), and the first control circuit (114) is further arranged to operably receive the second audio playback time stamp through the first Bluetooth communication circuit (111), and to operably control the first sampling-clock adjusting circuit (116) to calibrate a phase of the first audio sampling clock (CLK_A1) according to the second audio playback time stamp, so that a calibrated first audio sampling clock (CLK_A1) is synchronized with a current second audio sampling clock (CLK_A2).
5. The multi-member Bluetooth device (100) of claim 2 , wherein the first control circuit (114) is arranged to operably control the first clock adjusting circuit (113) to generate the first slave clock (CLK_P1S1) having a frequency substantially identical to a frequency of the first main clock (CLK_P1M) and a phase substantially aligned with a phase of the first main clock (CLK_P1M) according to the timing data of the first main clock (CLK_P1M), and the first control circuit (114) is further arranged to operably control the first clock adjusting circuit (113) to generate the second main clock (CLK_P2M) having a frequency substantially identical to the frequency of the first main clock (CLK_P1M) and a phase substantially aligned with the phase of the first main clock (CLK_P1M) according to the timing data of the first main clock (CLK_P1M) or a timing data of the first slave clock (CLK_P1S1).
6. The multi-member Bluetooth device (100) of claim 2 , wherein the second control circuit (124) is arranged to operably control the second clock adjusting circuit (123) to generate the second slave clock (CLK_P2S1) having a frequency substantially identical to a frequency of the second main clock (CLK_P2M) and a phase substantially aligned with a phase of the second main clock (CLK_P2M) according to the timing data of the second main clock (CLK_P2M).
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US17/831,744 US11751153B2 (en) | 2019-11-05 | 2022-06-03 | Multi-member bluetooth device capable of synchronizing audio playback between different bluetooth circuits |
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US17/081,652 US11405880B2 (en) | 2019-11-05 | 2020-10-27 | Main Bluetooth circuit and auxiliary Bluetooth circuit of multi-member Bluetooth device capable of synchronizing audio playback between different Bluetooth circuits |
US17/831,744 US11751153B2 (en) | 2019-11-05 | 2022-06-03 | Multi-member bluetooth device capable of synchronizing audio playback between different bluetooth circuits |
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US17/831,744 Active US11751153B2 (en) | 2019-11-05 | 2022-06-03 | Multi-member bluetooth device capable of synchronizing audio playback between different bluetooth circuits |
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